Scientific Name |
Common Name |
Number Aged |
Number Tested |
Average Age |
| Anoplopoma fimbria | Sablefish (Black cod) | 35917 | 8052 | 10.4 |
| Atheresthes evermanni | Kamchatka flounder | 120 | 24 | 8.93 |
| Atheresthes stomias | Arrowtooth flounder | 9761 | 2487 | 6.55 |
| Gadus macrocephalus | Pacific cod | 24057 | 7531 | 4.76 |
| Glyptocephalus zachirus | Rex sole | 2079 | 423 | 7.48 |
| Hippoglossoides elassodon | Flathead sole | 9713 | 2655 | 10.06 |
| Hippoglossoides robustus | Bering flounder | 237 | 48 | 8.61 |
| Lepidopsetta bilineata | Rock sole | 7802 | 1698 | 8.39 |
| Lepidopsetta bilineata | Southern rock sole | 482 | 101 | 10.16 |
| Lepidopsetta peracuata | Northern rock sole | 8559 | 2902 | 10.57 |
| Limanda aspera | Yellowfin sole | 21046 | 5643 | 12.54 |
| Merluccius productus | Pacific whiting | 47916 | 14150 | 6.3 |
| Microstomus pacificus | Dover sole | 3601 | 848 | 18.53 |
| Myoxocephalus polyacanthocephalus | Great sculpin | 403 | 245 | 6.94 |
| Pleurogrammus monopterygius | Atka mackerel | 22786 | 5435 | 4.07 |
| Pleuronectes quadrituberculatus | Alaska plaice | 3679 | 815 | 13.22 |
| Reinhardtius hippoglossoides | Greenland turbot | 169 | 55 | 12.01 |
| Sebastes aleutianus | Rougheye rockfish | 7234 | 2312 | 23.3 |
| Sebastes alutus | Pacific ocean perch | 26189 | 8087 | 12.98 |
| Sebastes ciliatus | Dark rockfish | 1881 | 739 | 18.56 |
| Sebastes polyspinis | Northern rockfish | 11994 | 2852 | 16.49 |
| Sebastes variabilis | Dusky rockfish | 4692 | 1186 | 13.37 |
| Sebastes variegatus | Harlequin rockfish | 647 | 501 | 12.69 |
| Sebastes zacentrus | Sharpchin rockfish | 570 | 154 | 12.57 |
| Theragra chalcogramma | Walleye pollock | 202917 | 55282 | 6.35 |
Average age is the average of all fish aged. Unageable and ranged samples were excluded. Samples may have been collected several years before data was released. Rock sole (Lepidopsetta bilineata) statistics are from samples collected before the species was split into southern rock sole (Lepidopsetta bilineata) and northern rock sole (Lepidopsetta peracuata).
Precision: Between-reader precision generally refers to the repeatability of an age when two different age readers age the same fish, with no knowledge of the other reader's age. For these twice-aged fish, an age is available from the reader (r) and a more experienced tester (t). Three measures of statistical precision can be calculated from the between-reader ages:
1. Percent Agreement (PA):
2. Average Percent Error (APE):![]()
3. Coefficient of Variation (CV):
Where n = the number of fish in the test sample and 
is the average age of a single fish.
APE and CV are averaged over all test samples. Often it is desirable to calculate PA, APE and CV broken down by age class. This is useful since precision estimates, especially PA, will vary with age. An advantage of both APE and CV is that they generally will not vary too much with age as they are scaled by
Kimura, D.K., and J.J. Lyons. 1991. Between-reader bias and variability in the age-determination process. Fish. Bull., U.S. 89:53-60.
